Xantrex Truecharge2 20 amp battery charger case fan operation

I have an Xantrex Truecharge2 20 amp battery charger that uses a case fan for cooling. The first generation Truecharge used large external heat sinks.

I'm trying to figure out if it's case fan is suppose to be running all the time or is controlled through an internal (pcb) temperature probe (on/off and/or speed control)

Everytime I've observed the Truecharge2 while charging batteries, the fan has been on, seems like at a full speed.

I don't know if the fan running all the time is normal?